Oil recommendation for 1984 Trans Am 5.0

[WyrTwister]

Originally Posted By: OVERKILL
Originally Posted By: WyrTwister

I think the 5.0l is / was a pretty good engine , just not high horse power .



Yeah, the 305 has the same stroke as the 350 but smaller bores. This seriously limited its power output potential due to valve shrouding and head selection. It was somewhat of an opposite approach to what Ford did with the 302, which had a short stroke and large bore.


Probably intended / designed for lower RPM torque intended of higher RPM HP ?

 

[ksj4477]

Originally Posted By: WyrTwister
Originally Posted By: ksj4477
Originally Posted By: john_pifer
If it has an oil consumption problem, it'll do it whether you use synth or dino.

I'd probably go with Pennzoil Platinum High Mileage 10W-30 and see how it likes it. Easy to get and cheap, at Walmart. Start with 6000-mile intervals and watch for any consumption. IF you get consumption, try something else.

Should clean out the engine nicely, too.



I'm unsure on oil consumption yet, it doesn't smoke much. Engine is quite dirty so It has to be coming from somewhere, probably intake seal. It hasn't left any drops on the garage floor though so it's nothing major but I don't want it to get worse.


Dirty on the inside or the outside .

If the valve seals are leaking , they can ( with the correct tooling ) be changed out w/o pulling the head .

Does it have a carburetor or TBFI ? We once had a 5.0l , early 80's Impala that had a carburetor with limited electronic control .


Q-Jet 4bbl

 

[CharBaby]

5W30 HM is all I've been using for the last 7-8 yrs in the Firebird FORMULA in my sig. Never a synthetic but most likely a blend.

 

[ksj4477]

Originally Posted By: FlyNavyP3
Originally Posted By: ksj4477
Hello, I’m looking for an oil recommendation for a 1984 Pontiac Trans Am with a 5L engine and 84,000 miles on it that I just purchased. I believe 5w30 or 10w30 conventional is what was in them from the factory. I live in PA and it won’t get driven in the winter so the really cold weather won’t be a problem. I was thinking maybe 10w40 conventional Castrol but was wondering if there was something better or if I should go to a high mileage oil. I don’t think I want to do synthetic because I’m worried about oil usage. Thank you!


Provided that it has good oil pressure I see no reason to run anything other than a HDEO 10W30. Rotella T4 10w30 is readliy available almost anywhere for a bargain price, has a great add pack for flat tappet or roller cams. If you wanted to step up to a 40, it's also available in 15W40. HDEO is my go to for just about any SBC/BBC street engine with reasonable spring pressure.



Is Rotella T4 used for diesel engines? The packaging threw me off a bit but I guess that would explain the extra protection.

Thanks!

 

[OVERKILL]

Originally Posted By: WyrTwister
Originally Posted By: OVERKILL
Originally Posted By: WyrTwister

I think the 5.0l is / was a pretty good engine , just not high horse power .



Yeah, the 305 has the same stroke as the 350 but smaller bores. This seriously limited its power output potential due to valve shrouding and head selection. It was somewhat of an opposite approach to what Ford did with the 302, which had a short stroke and large bore.


Probably intended / designed for lower RPM torque intended of higher RPM HP ?


Yeah, thought it really wasn't that great on that front either.

 

[ksj4477]

Originally Posted By: OVERKILL
Originally Posted By: WyrTwister
Originally Posted By: OVERKILL
Originally Posted By: WyrTwister

I think the 5.0l is / was a pretty good engine , just not high horse power .



Yeah, the 305 has the same stroke as the 350 but smaller bores. This seriously limited its power output potential due to valve shrouding and head selection. It was somewhat of an opposite approach to what Ford did with the 302, which had a short stroke and large bore.


Probably intended / designed for lower RPM torque intended of higher RPM HP ?


Yeah, thought it really wasn't that great on that front either.



1984 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2400 RPM (Q-Jet 4bbl)

It's definitely not a world beater. LOL Dished pistons, low lift cam... I guess they were just going for reliability instead of performance.

 

[Brigadier]

Originally Posted By: ksj4477
Originally Posted By: Brigadier
1984 - does it have the 4 BBL LG4/5 sp or the 4 bbl HO/auto combo? Didn't they have crossfire injection in those as an option as well?

Whatever engine is in there, and good 10W30 like Rotella will be fine.



Yes, it's the 4 BBL LG4/5 sp, it's a vin H and the vin on the engine matches. I think they may have had a crossfire option but I believe it was rare. Thanks, I'm thinking Rotella 10w30 will be the choice.


I had the same in a 1985 Z28. Only thing ever done besides maintenance items were two water pumps, two clutches, and an intake manifold gasket. I sold it to a young marine with 289k miles on the engine. It still chirped rubber when he drove off with it. I had to run 92 octane to keep it from pinging when the engine was lugging in 5th gear. Bosch Platinum spark plugs every 20-25k helped too.

 

[Brigadier]

Originally Posted By: ksj4477


1984 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2400 RPM (Q-Jet 4bbl)

It's definitely not a world beater. LOL Dished pistons, low lift cam... I guess they were just going for reliability instead of performance.


You can put a mild cam in it without tripping a CEL.

 

[OVERKILL]

Originally Posted By: Brigadier
Originally Posted By: ksj4477


1984 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2400 RPM (Q-Jet 4bbl)

It's definitely not a world beater. LOL Dished pistons, low lift cam... I guess they were just going for reliability instead of performance.


You can put a mild cam in it without tripping a CEL.


Being carb'd, I wouldn't expect it to get a CEL regardless, does it even have one? If it was EFI, then yeah, there are generally some cam spec constraints. Either way, the increase in output isn't going to be much, the heads aren't great.

 

[Brigadier]

Originally Posted By: OVERKILL
Originally Posted By: Brigadier
Originally Posted By: ksj4477


1984 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2400 RPM (Q-Jet 4bbl)

It's definitely not a world beater. LOL Dished pistons, low lift cam... I guess they were just going for reliability instead of performance.


You can put a mild cam in it without tripping a CEL.


Being carb'd, I wouldn't expect it to get a CEL regardless, does it even have one? If it was EFI, then yeah, there are generally some cam spec constraints. Either way, the increase in output isn't going to be much, the heads aren't great.


Yes, they had ECMs and CEL's in 1984.

 

[ksj4477]

I'm not sure what to think about the Rotella T4 oil... all I see are Diesel "C" classifications on it and no "S" classifications for gasoline engines. Am I safe using it?

Thank you!

 

[FCD]

It had it for years and i believe it has only been removed because it had too much phosphorous, which is not a problem really so ok to run in gas engines.

 

[OVERKILL]

Originally Posted By: Brigadier
Originally Posted By: OVERKILL
Originally Posted By: Brigadier
Originally Posted By: ksj4477


1984 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2400 RPM (Q-Jet 4bbl)

It's definitely not a world beater. LOL Dished pistons, low lift cam... I guess they were just going for reliability instead of performance.


You can put a mild cam in it without tripping a CEL.


Being carb'd, I wouldn't expect it to get a CEL regardless, does it even have one? If it was EFI, then yeah, there are generally some cam spec constraints. Either way, the increase in output isn't going to be much, the heads aren't great.


Yes, they had ECMs and CEL's in 1984.


OK, wasn't sure on the carb'd cars, as there wasn't much in the way of controls. My buddy's '80 didn't have anything that I know of, but that's the previous body style. Most of my experience is with Ford stuff, but I've been involved in a few SBC builds/projects, but we aren't talking stock stuff here, LOL!

 

[ksj4477]

Originally Posted By: FordCapriDriver
It had it for years and i believe it has only been removed because it had too much phosphorous, which is not a problem really so ok to run in gas engines.


Ok great! I figured it had to do with emissions or something which isn't an issue with an older car.

 

[FlyNavyP3]

Originally Posted By: ka9mnx
Synthetic or conventional HM 10w30. No HDEO needed. And No "Starburst", "ILSAC" or "Resource Conserving" oils. Try looking for a HM oil that is ACEA A3/B3 or A3/B4 and HTHS 3.5 or greater.

Take it from an old-school flat tappet owner. High ZDDP is also not needed.


The easiest non ILSAC or RC oil to find in a 10w30 especially for a reasonable price is a 10w30 HDEO. Why pay more for the same thing?

 

[FlyNavyP3]

SMI makes a killer Q-Jet, including for the electronic Q-Jet era. If you ever upgrade or modify, or heck even just need a rebuild he is THE Q-Jet Guy!

 

[jeff78]

Why don't you ask KITT to see what he recommends?



Sorry, somebody had to! One of my favorite shows when I was growing up.

 

[ksj4477]

Originally Posted By: jeff78
Why don't you ask KITT to see what he recommends?



Sorry, somebody had to! One of my favorite shows when I was growing up.


I did but he's grumpy and old and told me to [censored] off.

 

[Building3]

I have a similar situation, a 1972 Road Runner 440, original engine, never opened up, only drive it in non-snow above 32F. So basically from April through November. After probably too much analysis I decided on Rotella T4 10w-30. 10w-30 was the recommendation in the owner's manual. The Rotella T4 zinc and phosphorous levels are both above 1000, which is what the oils had back then. That seems to be the big concern: engine wear without sufficient Zn & P. These engines need the Zn and P. Even if you car has a catalyst, unless it burns oil, you don't need to worry about the phosphorous poisoning the catalyst. The EPA has continually extended the time it wants catalyst to last; I think now 150,000 miles, so most mainstream motor oils have reduced the phosphorous to make the catalysts last in the event the engine starts to "burn oil." I doubt your Trans Am or my Road Runner will ever see 150,000 miles. I went with T4 conventional because of all of the chatter I have heard about synthetics causing leaks: the oil companies say it can't happen, but too many people have posted that it does. So with an engine that does not leak, I decided not to take the chance.

 

[ksj4477]

Originally Posted By: Building3
I have a similar situation, a 1972 Road Runner 440, original engine, never opened up, only drive it in non-snow above 32F. So basically from April through November. After probably too much analysis I decided on Rotella T4 10w-30. 10w-30 was the recommendation in the owner's manual. The Rotella T4 zinc and phosphorous levels are both above 1000, which is what the oils had back then. That seems to be the big concern: engine wear without sufficient Zn & P. These engines need the Zn and P. Even if you car has a catalyst, unless it burns oil, you don't need to worry about the phosphorous poisoning the catalyst. The EPA has continually extended the time it wants catalyst to last; I think now 150,000 miles, so most mainstream motor oils have reduced the phosphorous to make the catalysts last in the event the engine starts to "burn oil." I doubt your Trans Am or my Road Runner will ever see 150,000 miles. I went with T4 conventional because of all of the chatter I have heard about synthetics causing leaks: the oil companies say it can't happen, but too many people have posted that it does. So with an engine that does not leak, I decided not to take the chance.


Makes sense. It has the cat but it will soon be removed... along with the air pump system. Thanks